Three phase stacked magnetic core section



April 1, 1958 VENNEAU 2,829,353

I THREE PHASE STACKED MAGNETIC CORE SECTION F'ild. -March 29. 1954 2Sheets-Sheet 1 April l, 1958 J. J. VIENNEAU 2,829,353

THREE PHASE STACKED MAGNETIIC CORE SECTION Filed March 29, 1954 2SheetsSheet 2 THREE PHASE STACKED MAQNETEQ SEQTIGN Jacob J. Vienneau,Pittsiield, Mass, assignor to Electric Company, a corporation oi- New itThis invention relates to a three-phase magnetic core section and moreparticularly, to an improved three-phase stacked magnetic core sectionof the split or divided leg and yoke type.

It is an object of this invention to provide an inexpensive low coreloss and exciting current three-phase stacked magnetic core section ofthe split or divided leg and yoke type.

My invention comprises a three-phase stacked magnetic core sectionhaving a plurality of stacked flat layers, each of said layers havingthree parallel split leg portions and parallel split yoke portionsextending perpendicular to said split leg portions and interconnectingthe ends of said split leg portions, said split leg and yoke portionstogether defining two window openings therebetween, said split leg andyoke portions each comprising two elongated rectangular-like striplaminations abutting each other along a lengthwise edge thereof, saidleg strip laminations having equal widths and said yoke striplaminations having equal widths, all of said strip laminationscomprising said layers having not more than six different lengths, eachof said layers and window openings having identical dimensions, eachcorner of each of said layers having a generally Z-shaped butt jointtherein between the split leg and yoke portions thereof, the Zshapedbutt joints in each corner of said core section in every immediatelyadjacent two of said layers offset with respect to each other, an outerstrip lamination of a split yoke portion of some of said layersextending continuously between an outermost two split leg portions ofsaid core section.

My invention further comprises a three-phase stacked magnetic coresection having a plurality of stacked fiat layers, each of said layershaving two outer legs and a central leg therebetween, all of said legsparallel to each other and parallel yokes extending between andperpendicular to said two outer legs and interconnecting the ends of allof said legs, all of said legs and yokes together defining two windowopenings therebetween, each of said layers and the window openingstherein having identical dimensions, all of said legs and yokescomprising two elongated rectangular like flat strips abutting eachother along a lengthwise edge thereof, all of the strips comprising saidlayers having identical widths, and all of said strips comprising saidlayers having not more than six different lengths, each of said layershaving a generally Z-shaped butt joint in each corner thereof betweenthe outer legs and yokes thereof, the Z-shaped butt joints in eachcorner of said core section in every immediately adjacent two of saidlayers staggered with respect to each other, in some of said layers allof the yoke strips therein interrupted by only one end of the centralleg strips of said some layers, in other of said layers all inner yokestrips of said other layers being interrupted by only one end of thecentral leg strips of said other layers, and the outer yoke strips ofsaid other layers extending uninterruptedly between said two outer legs.

The features of my invention which I believe to be novel are set forthwith particularity in the appended claims.

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My invention itself, however, both as to its organization and method ofoperation, together with further objects and advantages thereof, maybest be understood by reference to the following description taken inconnection with the accompanying drawings.

In the drawings, Fig.1 is a perspective view of one form of myinvention. Fig. 2 is an exploded perspective view of the transformercore section shown in Fig. 1. Fig. 3 is an exploded perspective view ofanother form of my invention. Like reference numerals will be usedthroughout the various figures to indicate identical parts.

Referring now to the drawings, in Fig. 1 is illustrated a three-leggedstacked three-phase magnetic core section in. As is well known in theelectrical transformer art, each leg of the magnetic core section isadapted to have electrical windings, illustrated in broken-line outline,disposed thereabout.

in Fig. 2, said magnetic core section 10 has its first four layersremoved therefrom. All of the layers have identical dimensions and areconstructed from elongated rectangular-like strips which preferably havea lengthwise grain orientation. All of said strips preferrably haveidentical widths, and as will be more clear hereinafter, said magneticcore section is built up out of strips having not more than sixdifferent lengths, thereby reducing the number of pieces to be handledand the cost of said magnetic core section.

The first layer 11 has a left-hand outer leg comprising strips 11 and Z,a right-hand outer leg comprising strips 2 and l, and a central legcomprising strips 2 and 2. Said three le s are disposed parallel to eachother and the two strips of each leg abut each other along a lengthwiseedge thereof. The central leg is disposed equidistant of the two outerlegs, and all of the strips 1 have identical lengths, and all of thestrips 2 have equal lengths.

The three legs of the core section are interconnected at the upper endsthereof by an upper yoke, and at the lower ends thereof by a lower yoke.Said upper and lower yokes each comprise strips 3 and 4, 4; strips 3 and4, i abutting each other along a lengthwise edge thereof. All of thestrips 3 have equal lengths, and all of the strips 4 have equal lengths.The yokes are parallel to each other and perpendicular to the legs ofthe bore section, and said yokes and legs together define two identicalwindow openings l8 therebetween.

it will be noted that the outer legs and yokes make a generally Z-shapedbutt joint with each other at each corner of the first layer 11. Thus,referring to the upper left-hand corner of first layer 11, the strip 1of the lefthand outer leg and the strip 3 of the upper yoke abut eachother along a line 12; strip 3. of the left-hand outer leg is abutted bythe left-hand strip 4 of the upper yoke along a line 13; and strip 2 ofthe left-hand outer leg abuts the left-hand strip 4 of the upper yokealong a line 14; lines 12, I13), and 14 being arranged with respect toeach other substantially in a Z-shaped manner.

The outer strips 3 of the upper and lower yokes extend continuouslybetween the upper and lower ends of the two outer legs to provide aneasy magnetic flux path along the outer perimeter of layer 11substantially free of cross grain or butt joint gap effect along thecentral portions of the yokes intersected by the central legs of thecore section. The inner strips 4, iof the upper and lower yokes however,do not extend continuously between the upper and lower ends of the twoouter legs. The inner strip 4, 4- of the upper yoke is interrupted bythe upper end of the left-hand central leg strip 2, and the inner strip4, 4 of the lower yoke is interrupted by the lower end of the right-handcentral leg strip 2.

The second layer 15 is identical to the first layer 11. Second layer 15in reality is first layer 11 rotated about an axis disposed in the planeof first layer 11 exasaassa.

tending perpendicular to the legs thereof. With the first and secondlayers reversed with respect to each other the Z-shaped butt joints ineach corner of said first and second layers will be offset or staggeredwith respect to each other. As will be obvious to those skilled in theart, said offset of the Z-shaped butt joints provides a structurallycompact core section having a low noise level, and reduces core lossesdue to corner cross grain and butt joint gap effect.

The third layer to is identical to the first layer ll except that theouter yoke strips 3 of layer ill in layer 16 have been replaced byinterrupted outer yoke strips 6, 6; and the central leg strips 2 and 2of layer 11 in layer 16 have been replaced by longer central leg strips5 and 5. Strips 5 have equal lengths, and strips 6 have equal lengths.The upper end of the left-hand central leg stri 5 of layer 16 interruptsthe upper inner and outer yoke strips 4, 4 and 6, 6; and the lower endof the righthand central leg strip 5 of layer 16 interrupts the innerand outer lower yoke strips 4, 4 and 6, 6. It will be noted that in anytwo immediately adjacent layers the butt joints in said adjacent layersformed between the central legs and yokes of said adjacent layers aresubstantially offset with respect to each other; said offset providing astructurally compact low noise level core section with low core losseasy magnetic flux paths along the perimeter of the window openings andthe outer perimeter of the core section substantially free of crossgrain and butt joint gap effect.

The fourth layer 17 is identical to third layer 16 and in reality islayer 16 rotated 180 about an axis disposed in the plane of layer 16extending perpendicular to the legs thereof. This sequence of layers 11,15, 16 and 17 is repeated until the magnetic core section is built up tothe desired thickness.

Referring now to Fig. 3, shown therein is another core section built upout of a single layer thereafter rotated first 180 about a horizontalaxis, then 180 about a vertical axis, and then 180 about a horizontalaxis to in effect give four different layers; whereas in Fig. 2 the coresection was built up out of two different layers each of which wasrotated 180 about a horizontal axis to in effect give four ditferentlayers.

The core section shown in Fig. 3 is magnetically equivalent to the coresection shown in Fig. 2. It will be noted that the upper half of thefirst layer 19 thereof is identical to the upper half of the first layer11 of Fig. 2, and that the lower half of first layer 19 is identical tothe lower half of the third layer 16 of Fig. 2. layer 19 can be formedby substituting the lower outer yoke strip 6, 6 of layer 16 of Fig. 2for the lower outer yoke strip 3 of layer 111 of Fig. 2; and thensubstituting the right-hand central leg strip 5 of layer 16 of Fig. 2for the righthand central leg strip 2 of layer 11 of Fig. 2.

The second layer 20 is first layer 19 rotated 180 about a horizontalaxis, the third layer 21 is second layer 29 rotated 180 about a verticalaxis, and the fourth layer 22 is third layer 21 rotated 180 about ahorizontal axis. This sequence of layers 19, 20, 21 and 22 is repeateduntil the magnetic core section is built up to the desired thickness.

In both the Fig. 2 and Fig. 3 forms of invention, only six differentstrips are used, preferably all of said strips having identical widthswhereby all of said strips can be cut from the same width stock.However, it is to be noted that if the yoke strips are assigneddifferent widths than the leg strips, still only six different piecesneed be used.

While there have been shown and described particular embodiments of theinvention, it will be obvious to those skilled in the art that changesand modifications may be made without departing from the invention, andthat it is intended by the appended claims to cover all such changesSaid first 4 and modifications as fall within the true spirit and scopeof the invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

l. A three-phase stacked magnetic core section having a plurality ofstacked flat layers, each of said layers having three parallel split legportions and parallel split yoke portions extending perpendicular tosaid split leg portions and interconnecting the ends of said split legportions, said split leg and yoke portions together defining two windowopenings therebetween, said split leg and yoke portions each comprisingtwo elongated rectangular-like strip laminations abutting each otheralong a lengthwise edge thereof, all of said leg strip laminationshaving equal widths and all of said yoke strip laminations having equalwidths, all of said strip laminations comprising said layers having notmore than six different lengths, each of said layers and window openingshaving identical dimensions, each corner of each of said layers having agenerally Z-shaped butt joint therein between the split leg and yokeportions thereof, the Z-shaped butt joints in each corner of said coresection in every immediately adjacent two of said layers offset withrespect to each other, an outer strip lamination of a split yoke portionof some of said layers extending continuously between an outermost twosplit leg portions of said core section.

2. A three-phase stacked magnetic core section having a plurality ofstacked flat layers, each of said layers having two outer legs and acentral leg therebetween, all of said legs parallel to each other andparallel yokes extending between and perpendicular to said two outerlegs and interconnecting the ends of all of said legs, all of said legsand yokes together defining two window openings therebetween, each ofsaid layers and the window openings therein having identical dimensions,all of said legs and yokes comprising two elongated rectangular-likeflat strips abutting each other along a lengthwise edge thereof, all ofthe strips comprising said layers having identical widths, and all ofsaid strips comprising said layers having not more than six differentlengths, each of said layers having a generally Z-shaped butt joint ineach corner thereof between the outer legs and yokes thereof, the Z-shaped butt joints in each corner of said core section in everyimmediately adjacent two of said layers staggered with respect to eachother, all of said layers having all inner yoke strips thereofinterrupted by only one end of the central leg strips thereof, some ofsaid layers having at least one outer yoke strip thereof extendingcontinuously between said two outer legs.

3. A three phase stacked magnetic core section having a plurality ofstacked fiat layers, each of said layers having three parallel split legportions and parallel split yoke portions extending perpendicular tosaid split leg portions and interconnecting the ends of said split legportions, said split leg and yoke portions together defining tr'o windowopenings therebetween, said split leg and yoke portions each comprisingtwo elongated rectangular-like strip laminations abutting each otheralong a lengthwise edge thereof, all of said strip laminations havingidentical widths, and all of said laminations comprising said layershaving not more than six different lengths, each of said layers andwindow openings having identical dimensions, each corner of each of saidlayers having a generally Z-shaped butt joint therein between the splitleg and yoke portions thereof, the Z- shaped butt joints in each cornerof said core section in every immediately adjacent two of said layersoffset with with respect to each other, both outer strip laminations ofthe split yoke portions of some of said layers extending continuouslybetween an outermost two split leg portions of said core section.

4. A three phase stacked magnetic core section having a plurality ofstacked flat layers, each of said layers asaasss having two outer legsand a central leg therebetween, all of said legs parallel to each otherand parallel yokes extending between and perpendicular to said two outerlegs and interconnecting the ends of all of said legs, all of said legsand yokes together defining two window openings therebetween, each ofsaid layers and the window openings therein having identical dimensions,all of said legs and yokes comprising two elongated rectangular-likeflat strips abutting each other along a lengthwise edge thereof, all ofthe strips comprising said layers having identical widths, and all ofsaid strips comprising said layers having not more than six differentlengths, each of said layers having a generally 2- shaped butt joint ineach corner thereof between the outer legs and yokes thereof, theZ-shaped butt joints in each corner of said core section in everyimmediately adjacent two of said layers staggered with respect to eachother, in some of said layers all of the yoke strips therein interruptedby only one end of the central leg strips of said some layers, in otherof said layers all inner yoke strips of said other layers beinginterrupted by only one end of the central leg strips of said otherlayers, and the outer yoke strips of said other layers extendinguninterruptedly between said two outer legs.

5. A rectangular-like three phase stacked magnetic core section having aplurality of stacked fiat layers, each of said layers having two outerlegs and a central leg therebetween, all of said legs parallel to eachother,

said central leg positioned equidistant of said two outer legs, parallelyokes extending between and perpendicular to said two outer legs andinterconnecting the ends of all of said legs, all of said legs and yokestogether defining two rectangular-like window openings therebetween,each of said layers and the window openings therein having identicaldimensions, all of said legs and yokes comprising two elongatedrectangular-like fiat strips abutting each other along a lengthwise edgethereof, all of the strips comprising said layers having identicalwidths, all of the strips comprising said layers having not more thansix different lengths, all of the strips comprising said layers having alengthwise grain orientation, each of said layers having a generallyZ-shaped butt joint in each corner thereof between the outer legs andyokes thereof, the Z-shaped butt joints in each corner of said coresection in every immediately adjacent two of said layers staggered withrespect to each other, every first one of said layers having both outeryoke strips thereof extending continuously between the two outer legsthereof, inner yoke strips of said first layers bisected by only one endof the central leg strips of said first layers whereby each of saidinner yoke strips is divided into two equal yoke strip portionsextending continuously only from one outer leg to a central leg, everysecond one of said layers comprising a layer identical to said firstlayers rotated about an axis disposed in said first layers perpendicularto the legs thereof, every third one of said layers having both innerand outer yoke strips thereof bisected by only one end of the centralleg strips thereof, every fourth one of said layers comprising a layeridentical to said third layers rotated 180 about an axis disposed insaid third layers perpendicular to the legs thereof.

6. A rectangular-like three-phase stacked magnetic core section having aplurality of stacked flat layers, each of said layers having two outerlegs and a central leg therebetween, all of said legs parallel to eachother, said central leg positioned equidistant of said two outer le s,parallel yokes extending between and perpendicular to said two outerlegs and interconnecting the ends of all of said legs, all of said legsand yokes together defining two rectangular-like window openingstherebetween, each of said layers and window openings therein havingidentical dimensions, all of said legs and yokes comprising twoelongated rectangular-like fiat strips abutting each other along alengthwise edge thereof, all of the strips comprising said layers havingidentical widths, all of the strips comprising said layers having notmore than six different lengths, all of the strips comprising saidlayers having a lengthwise grain orientation, each of said layers havinga generally Z-shaped butt joint in each corner thereof between the outerlegs and yokes thereof, the Z-shaped butt joints in each corner of saidcore section in every immediately adjacent two of said layers staggeredwith respect to each other, every first one of said layers having onlyone outer yoke strip thereof extending continuously between the twoouter legs thereof, every first one of said layers having the otherouter yoke strip and all inner yoke strips thereof bisected by only oneend of the central leg strips of said first layers, every second one ofsaid layers comprising layers identical to said first layers rotated 180about an axis disposed in said first layers perpendicular to the legsthereof, every third one of said layers comprising layers identical tosaid second layers rotated 180 about an axis disposed in said secondlayers parallel to the legs thereof, and every fourth one of said layerscomprising layers identical to said third layers rotated 180 about anaxis disposed in said third layers perpendicular to the legs thereof.

References Cited in the file of this patent UNITED STATES PATENTS1,891,178 Porter Dec. 13, 1932 2,467,823 Gordy Apr. 19, 1949 2,467,824Granfield Apr. 19, 1949

